How do liquids behave in space?
If you are in space and you throw liquid into space, does its become a solid or gas, or does it stay the same?
Dave - It fundamentally depends on the liquid and where you are in space.
If you throw water out in space, about where we are in the solar system, what's going to happen is that any water that evaporates off it isn't going to come back again - it's a hard vacuum. So it's going to boil away and, as it does that, it's going to get colder.
At some point it might freeze, but, eventually, it will still sublime and all turn into a gas.
If you did the same thing where it's very, very cold, out near Neptune or something, then it would be so cold that it would just freeze. If you did get a bit of evaporation, it will cool down and freeze and essentially stay there as a lump of ice.
If you use different liquids, different things will happen. Things like ionic liquids, they boil away so slowly that you could just have a blob of them them which sat around as a liquid permanently.
Chris - And what about on the international space station, if an astronaut sort of had one of those burps that occasionally has a little bit of follow through, for example, or just squeezed his packet drink a bit hard, what would you see?
Dave - So, if it's not going to evaporate then the major force affecting it is surface tension, the only force which is left. So essentially, you get a huge droplet of water which is kind of held together by surface tension that would bobble around and just sit there floating in space until he'll either drinks it or it hits something.